1. Field of the Invention
The present invention relates generally to wavelength selective cross-connect switches (WSXC), and particularly to WSXC switches using micro-electro mechanical system (MEMS) shutter arrays.
2. Technical Background
Communication networks increasingly rely upon optical fiber for high-speed, low-cost transmission. Optical fibers were originally envisioned as an optical replacement for electronic transmission media, such as high-speed coaxial cable and lower-speed twisted-pair cable. However, even high-speed optical fibers are limited by the electronics at the transmitting and receiving ends, generally rated at a few gigabits per second, although 40 Gbit/s systems have been prototyped. Such high-speed electronic systems are expensive and still do not fully exploit the inherent bandwidth of fiber-optic systems. On the other hand, communication networks comprised of only optical components offer many intrinsic advantages over systems that use electronics within any part of the principal transmission path.
Wavelength division multiplexing (WDM) is pervasive in optical communication systems. Generally, wavelength division multiplexing (WDM) electronically impresses different data signals upon different carrier frequencies, all of which are carried by a single optical fiber. Recent research and development has suggested that an all-optical network can be constructed having switching nodes that can switch the separate WDM channels (carrier frequencies) in different directions without the necessity of converting the optical signals to electronic signals. If such optical switching can be accomplished with simple optical components, a sophisticated optical network can be constructed at relatively low cost. Moreover, the high-speed electronics of the optical network can be confined to the system end terminals that require speeds of only the individual channels and not of the total throughput of the system.
One aspect of the present invention is an optical switch for selectively switching wavelength channels between two optical signals. The optical switch includes two dispersive elements, where each dispersive element receives an optical input signal and disperses it into a plurality of wavelength-separated input channels, and a micro-electro mechanical system (MEMS) shutter array receiving the plurality of wavelength-separated input channels from each of the dispersive elements and operative for selectively switching one or more of the wavelength-separated input channels between the optical signals.
Additional features and advantages of the invention will be set forth in the detailed description which follows, and in part will be readily apparent to those skilled in the art from that description or recognized by practicing the invention as described in the detailed descriptions which follows, the claims as well as the appended drawings.
It is to be understood that both the foregoing general description and the following detailed description are merely exemplary of the invention, and are intended to provide an overview or framework for understanding the nature and character of the invention as it is claimed. The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate various features and embodiments of the invention, and together with the description serve to explain the principles and operation of the invention.